Microbiological,colour and sensory changes of refrigerated chicken legs treated with selected phosphates

The influence of dipping chicken legs for 10 min in 5% solutions containing monopotassium phosphate (MKP), monosodium phosphate (MSP), sodium pyrophosphate (SPP), or trisodium phosphate (TSP) on aerobic plate counts (APC), Hunter colour, odour, and appearance of chicken legs were assessed. TSP had greater antimicrobial activity than MKP, SPP or MSP. Chicken legs treated with 5% TSP for 10 min had aerobic plate counts nearly 3 logs lower than controls and other treatments after 12 days of storage at 4°C. Shelf-life of legs could be extended to 16 days with 7.5 or 10% TSP treatment. TSP-treated legs were darker, less red, and less yellow than untreated legs. TSP-treated legs had a detectable chemical odour at levels greater than 10%; however, at 5% TSP, treated legs had odour and appearance resembling fresh controls for up to 16 days at 4°C. Dipping chicken legs in 5–10% TSP could extend shelf-life up to 8 days during refrigerated storage without adversely affecting sensory quality.     

MICROBIOLOGICAL AND SENSORY ANALYSES OF REFRIGERATED CATFISH FILLETS TREATED WITH ACETIC AND LACTIC ACIDS

The influence of acetic acid (AA) and/or lactic acid (LA) dips on microbial numbers, pH, and sensory scores of catfish fillets was assessed during storage at 4C. Fillets were treated by dipping in 4C AA and/or LA solutions for 0–60s. Fillets treated with either 3–4% AA or 2% AA and 2% LA for 30–60s suppressed growth of aerobic microorganisms for 4 days and extended shelf-life to 16 days. Treatment with either 3–4% LA or 1% AA and 1% LA for 5–60s prolonged microbiological shelf life to 12 days. AA had greater antimicrobial activity than LA. Fillets treated with AA alone or combinations of AA and LA were liked less by sensory panels than controls due to acidic odor and flesh discoloration. Thus, concentrations of AA or LA greater than 2% or exposure times greater than 30s are not recommended for catfish fillets.     

Inhibitory effect of oxalic acid on bacterial spoilage of raw chilled chicken

Oxalic acid was evaluated as a treatment for reducing populations of naturally occurring microorganisms on raw chicken. Raw chicken breasts were dipped in solutions of oxalic acid (0, 0.5, 1.0, 1.5, and 2.0%, wt/vol) for 10, 20, and 30 min, individually packed in oxygen-permeable polyethylene bags, and stored at 4 degrees C. Total plate counts of aerobic bacteria and populations of Pseudomonas spp. and Enterobacteriaceae on breasts were determined before treatment and after storage for 1, 3, 7, 10, and 14 days. The pH and Hunter L, a, and b values of the breast surface were measured. Total plate counts were ca. 1.5 and 4.0 log CFU/g higher on untreated chicken breasts after storage for 7 and 14 days, respectively, than on breasts treated with 0.5% oxalic acid, regardless of dip time. Differences in counts on chicken breasts treated with water and 1.0 to 2.0% of oxalic acid were greater. Populations of Pseudomonas spp. on chicken breasts treated with 0.5 to 2.0% oxalic acid and stored at 4 degrees C for 1 day were less than 2 log CFU/g (detection limit), compared with 5.14 log CFU/g on untreated breasts. Pseudomonas grew on chicken breasts treated with 0.5% oxalic acid to reach counts not exceeding 3.88 log CFU/g after storage for 14 days. Counts on untreated chicken exceeded 8.83 log CFU/g at 14 days. Treatment with oxalic acid caused similar reductions in Enterobacteriaceae counts. Kocuria rhizophila was the predominant bacterium isolated from treated chicken. Other common bacteria included Escherichia coli and Empedobacter brevis. Treatment with oxalic acid caused a slight darkening in color (decreased Hunter L value), retention of redness (increased Hunter a value), and increase in yellowness (increased Hunter b value). Oxalic acid has potential for use as a sanitizer to reduce populations of spoilage microorganisms naturally occurring on raw chicken, thereby extending chicken shelf life.     

高压静电场对不同包装冷鲜鸡肉贮藏过程中产品特性的影响

为探索高压静电场（high voltage electrostatic field,HVEF）对冷鲜鸡肉贮藏过程中产品特性的影响,将冷鲜鸡胸肉分别进行4 种不同条件下的贮藏：托盘包装-HVEF贮藏（托盘静电）、托盘包装普通贮藏（托盘对照）、未包装-HVEF贮藏（未包装静电）和未包装普通贮藏（未包装对照）,冷藏温度为4 ℃,HVEF输出电压为4000 V,测定不同贮藏条件下冷鲜鸡肉贮藏过程中感官指标、pH值、颜色、硫代巴比妥酸反应物（thiobarbituricacid reactive substance,TBARs）值和菌落总数变化。结果表明：HVEF贮藏条件下,冷鲜鸡肉的色泽、组织状态和气味的感官评分均高于相同贮藏条件下的对照组,托盘包装和HVEF处理的结合可有效减缓冷鲜鸡肉pH值的升高,保持色泽的稳定性,延缓TBARs值的上升和抑制微生物生长,托盘静电贮藏条件下冷鲜鸡肉的货架期可达8 d,比其他条件可延长2 d。因此,HVEF在冷鲜鸡肉贮藏保鲜中的应用具有一定的可行性。     

Validation of a 2 percent lactic acid antimicrobial rinse for mobile poultry slaughter operations

Poultry processing antimicrobial interventions are critical for pathogen control, and organic, mobile operations in Washington seek alternatives to chlorine. Laboratory and field studies (three replications each) evaluated lactic acid efficacy as a chlorine alternative. For the laboratory study, retail-purchased, conventionally processed chicken wings inoculated with Salmonella were randomly assigned to the following treatments: Salmonella inoculation followed by no treatment (10 wings) or by 3-min rinses of water, 50 to 100 ppm of chlorine, or 2% lactic acid (20 wings for each rinse treatment). Wings were sampled for Salmonella enumeration on xylose lysine desoxycholate agar. During pastured poultry processing at mobile slaughter units for each field study replication, 20 chicken carcasses were randomly assigned to each treatment: untreated control or 3-min immersion in lactic acid or chlorine. Whole-carcass rinses were examined for aerobic plate count (APC) on tryptic soy agar and coliforms on violet red bile agar. Untreated controls were also examined for Salmonella. In the laboratory study, lactic acid produced a significant (P < 0.01) Salmonella reduction compared with the inoculated no-rinse, water, and chlorine treatments, which were statistically similar to each other. In the field study, no Salmonella was detected on untreated controls. Lactic acid produced significant >2-log (P < 0.01) reductions in APC and coliforms, whereas chlorine resulted in slight, but significant 0.4-log reductions (P < 0.01) and 0.21-log reductions (P < 0.05) in APC and coliforms compared with untreated controls. Considering laboratory and field studies, lactic acid produced greater reductions in Salmonella, APC, and coliforms, validating its effectiveness as a chlorine alternative in mobile poultry slaughter operations.     

LACTIC ACID DIPPING FOR INHIBITING MICROBIAL SPOILAGE OF REFRIGERATED CATFISH FILLET PIECES

Subdivided catfish fillets were dipped in chilled (7°C) solutions of 1.70% and 2.55% (v/v) lactic acid (LA) for 10 min. Control pieces were not dipped. All pieces were individually placed in sterile plastic bags and stored either at 7°C for 3 days or on ice in a 2°C cold room for 6 days. Aerobic plate count (APC) was periodically determined using plate count agar pour plate and Petrifilm? film methods. At 7°C, APC for both LA treatments was significantly (P<0.05) lower than for controls during 3 days of storage. Day 3 APC values for 1.70% and 2.55% LA samples were lower than controls by 1.3 and 2.3 logs, respectively. Similarly, after 6 days at 2°C the APC values for 1.70% and 2.55% LA samples were 1.3 and 3.1 logs lower, respectively, than for control samples. Throughout storage at both temperatures, 2.55% LA samples had significantly (P<0.05) lower APC than 1.70% LA samples. No significant (P<0.05) difference was observed between pour plate and Petrifilm? APC methods, although APC values for the latter method were consistently slightly higher. Untrained sensory evaluation panelists could not consistently distinguish between control and 1.70% LA catfish pieces that were dipped in batter, breaded, and fried. Control, 1.70% LA, and 2.55% LA-dipped pieces were not rated as significantly different (P<0.05) in whiteness of flesh, tartness, and overall flavor acceptability. Acid dipping of catfish could be useful for extending the refrigerated shelf-life of unfrozen catfish fillets.     

Postprocessing antimicrobial treatments to control Listeria monocytogenes in commercial vacuum-packaged bologna and ham stored at 10 degrees C

The antilisterial effect of chemical dipping solutions on commercial bologna and ham slices, inoculated (3 to 4 log CFU/ cm2) after processing, was evaluated during storage in vacuum packages at 10 degrees C. Samples were inoculated with a 10-strain composite of Listeria monocytogenes and subsequently immersed (25+/-2 degrees C) for 2 min in 2.5% acetic acid (AA), 2.5% lactic acid (LA), 5% potassium benzoate (PB), or 0.5% Nisaplin (commercial form of nisin, equivalent to 5,000 IU/ml of nisin) solutions, either singly or sequentially (Nisaplin plus AA, Nisaplin plus LA, or Nisaplin plus PB), and then vacuum packaged and stored at 10 degrees C for 48 days. In addition to microbiological analysis, sensory evaluations were performed on uninoculated samples treated with AA, LA, or PB. Initial reductions (day 0) of the pathogen, compared with the controls, on bologna and ham samples treated with AA, LA, or PB ranged from 0.4 to 0.7 log CFU/cm2. Higher (P < 0.05) initial reductions (2.4 to 2.9 log CFU/cm2) were obtained for samples treated with Nisaplin alone and when followed by AA, LA, or PB. L. monocytogenes populations on control bologna and ham samples increased from 3.4 log CFU/cm2 (day 0) to 7.4 and 7.8 log CFU/ cm2, respectively, in 8 days at 10 degrees C. Listericidal effects were observed for all treatments tested, except for Nisaplin applied on its own, during storage at 10 degrees C. The sequential treatment of Nisaplin plus LA reduced L. monocytogenes to undetectable levels in both products at the end of storage. The sequential treatments were also found to inhibit growth of spoilage microorganisms. Sensory evaluations indicated that dipping (2 min) of ham samples in AA (2.5%), LA (2.5%), or PB (5%) led to lower sensory scores. However, since results of this study indicated that these treatments caused extensive listericidal effects, there is possibly a potential to reduce the levels of chemicals applied and still achieve adequate antilisterial activity without major negative effects on product quality.     

Effect of various chemical decontamination treatments on natural microflora and sensory characteristics of poultry

Regulation (EC) No. 853/2004 of the European Parliament and of the Council provides a legal basis permitting the use of antimicrobial treatments to remove surface contamination from poultry. This paper reports the results of research into the effects on natural microflora, pH, and sensorial characteristics achieved by dipping chicken legs (15 min, 18+/-1 degrees C) into solutions (wt/vol) of 12% trisodium phosphate (TSP), 1200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), 220 ppm peroxyacids (Inspexx 100; PA), and water. Samples were collected immediately after evisceration, subjected to the treatments listed or left untreated (control) and tested after 0, 1, 3 and 5 days of storage (3 degrees C+/-1 degrees C). For most microbial groups similar counts were observed on water-dipped and on untreated legs. All the chemical compounds were effective in reducing microbial populations throughout storage, with TSP, ASC and CA showing the strongest antimicrobial activity. The average reductions (mean+/-standard deviation) relative to untreated samples caused by chemical treatments when considering simultaneously all storage days ranged (log(10) cfu/g skin) from 0.53+/-0.83 (PA) to 1.98+/-0.62 (TSP) for mesophilic aerobic counts, from 0.11+/-0.89 (PA) to 1.27+/-1.02 (CA) (psychrotrophs), from 1.34+/-1.40 (PA) to 2.15+/-1.20 (CA) (Enterobacteriaceae), from 1.18+/-1.24 (PA) to 1.98+/-1.16 (CA) (coliforms), from 0.66+/-0.99 (PA) to 1.86+/-1.80 (TSP) (Micrococcaceae), from 0.54+/-0.74 (TSP) to 2.17+/-1.37 (CA) (enterococci), from 0.72+/-0.66 (TSP) to 2.08+/-1.60 (CA) (Brochothrix thermosphacta), from 0.78+/-1.02 (PA) to 1.99+/-0.96 (TSP) (pseudomonads), from 0.21+/-0.61 (PA) to 1.23+/-0.60 (TSP) (lactic acid bacteria), and from 1.14+/-0.89 (PA) to 1.45+/-0.61 (ASC) (moulds and yeasts). The microbial reductions throughout storage increased, decreased, or did not vary, in accordance with microbial group and chemical involved. Similar pH values were observed for untreated samples and for those dipped in PA and water on all sampling days. ASC-treated samples showed a lower pH than controls to day 1. TSP-treated legs exhibited the highest pH values and CA-treated ones the lowest, throughout storage. Hedonic evaluation (nine-point structured scale, untrained panellists) showed similar colour, smell and overall acceptability scores for dipped and untreated samples on day 0 and day 1. From day 3 sensorial attributes scored lower for untreated, PA- and water-dipped legs, as compared to legs treated with TSP, ASC and CA. Only for these three groups of samples were average scores higher than 6 (shelf-life limit value) observed by the end of storage. Results from the present study suggest that the treatments tested improve the microbial quality of chicken without adverse sensorial effects.     

Enhanced Inhibition of Listeria monocytogenes by Glycerol Monolaurate with Organic Acids

Glycerol monolaurate (ML) inhibition of Listeria monocytogenes was affected by pH and testing matrix. We investigated antimicrobial effects of ML combined with acetic, benzoic, citric, and lactic acids (AA, BA, CA, and LA) on L. monocytogenes in broth medium and crawfish tail meat. Minimum inhibitory concentrations were lower when ML was combined with each acid in dual combination. ML combined with sublethal amounts of AA, BA, or LA gave greater inhibition than for the most active compound alone. No interaction occurred between ML and CA. ML had no influence on pH of media containing organic acids. ML or LA in crawfish tail meat had reduced activity. ML activity was influenced by type of organic acid used. Combining ML with organic acids may provide similar protection to other precooked ready-to-eat foods.     

Microbial and color quality of fillets obtained from steam-pasteurized deheaded and eviscerated whole catfish

The present study reports on the microbiological quality and surface color of skinless catfish fillets obtained from steam-treated catfish. Total aerobic (APC), psychrotrophic (PPC), coliform (CPC) plate counts, and Hunter color analysis of fillets were performed after treatment and during 14 days of storage at 4°C. Results indicated that as steam treatment duration increased (15–120 s), greater reduction of fillet microflora population was achieved. Microbial counts on fillets obtained from steam-treated catfish were lower than controls at all sample times. Steam treatment for 120 s produced fillets with APC, PPC, and CPC that were 1·6, 1·7, and 1·9 log₁₀cfu g⁻¹lower than control fillets after 4 days at 4°C. Hunter color analysis of fillets revealed no color differences (L, a, b, and Whiteness) between steam-treated and control fillets. The reduction of skin microbial loads by steam prior to skinning of catfish resulted in fillets with superior microbiological quality and no Hunter surface color changes.     

Muscle Microstructure and Sensory Attributes of Organic Acid-Treated Beef Strip Loins

Beef strip loins were cut into halves and one-half sprayed with a 2% lactic and acetic acid mixture (v/v) and corresponding halves used as controls. Strip loins were stored at – 1°C for 0, 7, 14, 28, 56, 84, or 112 days and evaluated for sensory and microstructural properties. Cooking loss and Hunter color ‘L’ values decreased (P<0.01) and thiobarbituric acid reactive substances (TBARS) increased (P<0.01) over 112 days. No differences (P>0.05) were detected for cooking loss, shear force, TBARS, or Hunter color values between treatments. Flavor intensity increased (P<0.05) over time; however, no other sensory differences (P>0.05) were noted for storage time or acid treatment. Organic acids appeared to denature muscle microstructure without having any effects on physical and sensory attributes.     

Microbiological and sensory quality of sonicated calcium-added orange juice

Ultrasonic treatments were applied at a frequency of 20 kHz and three wave amplitudes for 2, 4, 6, 8 and 10 min, to orange juice with added calcium. Aerobic mesophilic count (AMC), yeast and mold counts (YMC), Hunter color values, ascorbic acid concentration and sensory attributes were measured. Wave amplitude of 89.25 μm for 8 min was selected for final treatment of the juice, and storage studies were performed at 4 and 10 °C. Microbial inactivation followed Geeraerd, Herremans, and Van Impe (2000) model. The treatment decreased AMC by 1.38 log CFU/ml, and YMC by 0.56 log CFU/ml. The sensory quality of the juice was slightly deteriorated after treatment, but during storage, it degraded faster for controls than for treated samples. Controls were rejected by the sensory panel after 6 days storage at 4 °C due to off-flavor, and ultrasonicated juice after 10 days due to off-odor. Consequently, a shelf-life extension of 4 days was achieved. At both times (6 or 10 days) AMC reached 6.5 log CFU/ml, which suggests a relation between sensory deterioration and bacterial activity. Sonication also affected color and decreased ascorbic acid content. This study shows that ultrasonication may be useful to extend the shelf-life of orange juice.     

EXTENDED STORAGE LIFE OF LITCHI FRUIT USING CONTROLLED ATMOSPHERE AND LOW TEMPERATURE

The postharvest quality of litchi (Litchi chinensis Sonn.) cv. Bombay stored under controlled atmosphere (CA) at 3.5% O₂and 3.5% CO₂, 2C temperature and 92–95% relative humidity was studied. Fruits were also held in regular atmosphere (RA) maintained at 2C temperature and 92–95% relative humidity. Fruits kept at normal ambient conditions were used as controls. Various quality attributes measured revealed that fruits stored in CA exhibited Hunter “a” values of 11.2 after 56 days of storage, indicating the beneficial effect of CA on retaining the red color of litchi fruits. Fruits held in RA exhibited Hunter “a” values (7.9) lower than that of CA‐stored litchi, showing that browning of litchi was noticeable in RA. Loss of weight was lowest (4.9%) for the fruits stored in CA compared to those stored in RA (11.0%) and control (33.1%). Loss of acidity and ascorbic acid content of fruits stored in CA were less than that of RA. The smallest increase of litchi firmness and pericarp puncture strength of 2.2 and 3.9 times of initial level, respectively, were observed even after 56 days of storage in CA. Total soluble solid of litchi increased from 19.3° Brix at harvest to 23.0° Brix until 48 days of storage in CA after which it declined to 22.8 °Brix. The sensory evaluation of aril color and taste showed that the fruits held in CA were rated good throughout 56 days of storage.     

Post process control of Listeria monocytogenes on commercial frankfurters formulated with and without antimicrobials and stored at 10 degrees C

The antilisterial effect of postprocess antimicrobial treatments on commercially manufactured frankfurters formulated with and without a 1.5% potassium lactate-0.05% sodium diacetate combination was evaluated. Frankfurters were inoculated (ca. 3 to 4 log CFU/cm2) with 10-strain composite Listeria monocytogenes cultures originating from different sources. The inocula evaluated were cells grown planktonically in tryptic soy broth plus 0.6% yeast extract (30 degrees C, 24 h) or in a smoked sausage homogenate (15 degrees C, 7 days) and cells that had been removed from stainless steel coupons immersed in an inoculated smoked sausage homogenate (15 degrees C, 7 days). Inoculated frankfurters were dipped (2 min, 25 +/- 2 degrees C) in acetic acid (AA; 2.5%), lactic acid (LA; 2.5%), potassium benzoate (PB; 5%), or Nisaplin (commercial form of nisin; 0.5%, equivalent to 5,000 IU/ml of nisin) solutions, or in Nisaplin followed by AA, LA, or PB, and were subsequently vacuum packaged and stored for 48 days at 10 degrees C. In addition to microbiological analyses, sensory evaluations were performed with uninoculated samples that had been treated with AA, LA, or PB for 2 min. Initial L. monocytogenes populations were reduced by 1.0 to 1.8 log CFU/cm2 following treatment with AA, LA, or PB solutions, and treatments that included Nisaplin reduced initial levels by 2.4 to >3.8 log CFU/ cm2. All postprocessing treatments resulted in some inhibition of L. monocytogenes during the initial stages of storage of frankfurters that were not formulated with potassium lactate-sodium diacetate; however, in all cases, significant (P < 0.05) growth occurred by the end of storage. The dipping of products formulated with potassium lactate-sodium diacetate in AA or LA alone--or in Nisaplin followed by AA, LA, or PB-increased lag-phase durations and lowered the maximum specific growth rates of the pathogen. Moreover, depending on the origin of the inoculum, this dipping of products led to listericidal effects. In general, differences in growth kinetics were obtained for the three inocula that were used to contaminate the frankfurters. Possible reasons for these differences include the presence of stress-adapted subpopulations and the inhibition of the growth of the pathogen due to high levels of spoilage microflora. The dipping of frankfurters in AA, LA, or PB did not (P > 0.05) affect the sensory attributes of the product when compared to the control samples. The data generated in this study may be useful to U.S. ready-to-eat meat processors in their efforts to comply with regulatory requirements.     

Storage Stability of Vacuum Packaged Frozen Pork Sausage Containing Soy Protein Concentrate, Carrageenan or Antioxidants

Fresh pork sausage patties containing carrageenan, without or with soy protein and an antioxidant were packaged with or without vacuum. They were evaluated for sensory properties, visual color, thiobarbituric acid reactive substances (TBARS), and Hunter color ‘L’, ‘a’, ‘b’ values at 4-wk intervals during 16 wk frozen storage. Rosemary extract was as effective as butylated hydroxytoluene (BHT)/propyl gallate (PG)/citric acid (CA) in antioxidant properties, but patties with BHT/PG/CA showed less surface discoloration (P < 0.05). In fat-control (FC) products, antioxidants combined with vacuum packaging provided optimum protection against rancidity. With vacuum packaging (VP), reduced-fat products maintained acceptable quality (TBARS and sensory properties) during 16 wks frozen storage.     

Effects of hot water and lactic acid treatment of beef trimmings prior to grinding on microbial, instrumental color and sensory properties of ground beef during display

The impact of 82°C hot water (HW) or 5% lactic acid (LA) applied aerobically or by vacuum to beef trimmings prior to grinding on Salmonella Typhimurium (ATCC 1769NR; ST), Escherichia coli (ATCC 11775; EC), coliform (CO), aerobic plate count (APC), instrumental color and sensory characteristics of ground beef through simulated retail display was investigated. For this, beef trimmings were inoculated with a mixture (7 log CFU/ml each) of ST and EC, and treated either aerobically or under vacuum in a tumbler with HW or LA antimicrobials. Trimmings were ground, packaged and sampled on days 0, 1, 2, 3 and 7 of display for ST, EC, CO, APC, sensory and instrumental color characteristics. Vacuum HW or LA application had no additive effect (P>0.05) when compared with aerobic application for reducing EC, ST, CO or APC. However, lactic acid was effective for reducing (P<0.05) EC, CO and APC, but reduced ground beef redness.     

加工工艺对白切鸡品质及微生物状况的影响

为探究加工工艺对白切鸡品质的影响,本研究采用在95 ℃卤水中浸煮18、20、22 min和冰水冷浸8、 15 min的工艺组合加工白切鸡,测定产品得率、保水性、pH值、色泽、质构特性和微观结构等品质指标及其在室 温放置2 h后的菌落总数。结果表明,相同冷却条件下,随着浸煮时间的延长,白切鸡的产品得率显著降低,鸡肉 的保水性显著提升（P＜0.05）,肌纤维间隙变小,室温条件贮藏2 h后菌落总数显著减少（P＜0.05）。冰水冷浸 15 min组白切鸡质构特性显著优于冷浸8 min组（P＜0.05）。感官评价结果显示：浸煮18 min组白切鸡的口感、风 味得分显著低于其他处理组（P＜0.05）;冷浸时间对口感的影响最为显著（P＜0.05）;通过浸煮20 min、冰水冷 浸15 min得到的白切鸡感官评分最高,结合质构特性得分,推荐为较优的加工方式。本研究为进一步探索白切鸡的 标准化和工业化生产提供了一定的理论支持和参考。     

Inhibition of quality loss in chilled megrim (Lepidorhombus whiffiagonis) by employing citric and lactic acid icing

This study focuses on the quality retention of megrim (Lepidorhombus whiffiagonis) during chilled storage. Aqueous solutions of two different concentrations of citric (CA) and lactic (LA) acids were employed as icing media (0.125% CA–0.050% LA and 0.175% CA–0.050% LA, respectively; w/v). The effects of each solution on microbial activity, lipid damage and sensory acceptance were monitored for up to 13 days of storage. Lower (P < 0.05) bacterial growth was detected according to microbiological (aerobe and psychrotroph counts) and chemical (trimethylamine‐N and pH) assessments, which led to an enhancement of sensory appreciation. Whereas control fish were determined as unacceptable at day 13, the acid‐iced fish were still acceptable at that time. Concerning lipid damage, an inhibitory effect (P < 0.05) on fluorescent compound formation was observed in the acid‐iced fish. Present results allow to conclude that the use of a CA–LA icing system can provide a profitable strategy to obtain higher quality chilled fish.     

The impact of single antimicrobial intervention treatment with cetylpyridinium chloride, trisodium phosphate, chlorine dioxide or lactic acid on ground beef lipid, instrumental color and sensory characteristics

The effects of antimicrobial agents on ground beef were evaluated to determine if instrumental color, sensory or odor characteristics were impacted. Trimmings were treated with 0.5% cetylpyridinium chloride (CPC), 200-ppm chlorine dioxide (CLO), 0.5% lactic acid (LA), 10% trisodium phosphate (TSP), or an untreated control (C). Ground beef made from trimmings with CLO and TSP were similar (P > 0.05) in L(?) values to the control; however, samples were redder (a(?); P<0.05) than the control. Likewise, sensory panelists found ground beef from the CPC and TSP treatments redder (P<0.05) for worst point color than the control by day 2 of display. The CLO, CPC and TSP treatments were similar (P>0.05) to the control in beef odor intensity until day 3 of display. Therefore, the use of antimicrobial agents on beef trimmings may not adversely affect, and may improve bulk ground beef color and odor characteristics.     

CARBON MONOXIDE EFFECTS ON COLOR AND MICROBIAL COUNTS OF VACUUM-PACKAGED FRESH BEEF STEAKS IN REFRIGERATED STORAGE

Ribeye, top round, and eye of round steaks were treated for 30 min with 100% carbon monoxide (CO), vacuum packaged, and held in refrigerated storage. Instrumental color determinations (L*, a*, and b* values) were made on uncooked ribeye and round steaks every 7 days. Aerobic plate counts (APC), psychrotrophs, and lactic acid bacteria (LAB) were determined on eye of round samples after 1, 4, and 8 weeks. Initially, CO-treated steaks were more red (higher a* values) than untreated steaks. The a* values of treated steaks decreased during storage; at 6 weeks no differences existed due to CO treatment. CO-treated steaks were more yellow (higher b* values) at all storage times than untreated steaks. APC of CO-treated samples were 1 log cycle lower than control after 8 weeks in storage; LAB counts were nearly 1 log cycle lower for CO-treated samples after 8 weeks. Psychrotrophic counts were similar for control and CO-treated samples during the first 4 weeks of refrigerated storage but were nearly 2 log cycles lower for CO-treated samples after 8 weeks. These data suggest that CO-treated steaks are more red and that they have extended shelf-lives compared with untreated, vacuum-packaged steaks.